21005511126 has 16 divisors (see below), whose sum is σ = 42013038528. Its totient is φ = 7001501000.

The previous prime is 21005511113. The next prime is 21005511133. The reversal of 21005511126 is 62111550012.

It is a junction number, because it is equal to n+sod(n) for n = 21005511096 and 21005511105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74401 + ... + 218051.

It is an arithmetic number, because the mean of its divisors is an integer number (2625814908).

Almost surely, 2^21005511126 is an apocalyptic number.

21005511126 is an abundant number, since it is smaller than the sum of its proper divisors (21007527402).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21005511126 is a wasteful number, since it uses less digits than its factorization.

21005511126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168027.

The product of its (nonzero) digits is 600, while the sum is 24.

The spelling of 21005511126 in words is "twenty-one billion, five million, five hundred eleven thousand, one hundred twenty-six".